Geothermal well test analysis using the pressure derivative: Some common issues and solutions

- Three common issues for geothermal pressure transient analysis are investigated.
- Downflows, slow valve closing and two-stage pump shut-down are studied.
- Characteristic appearance of these issues on pressure derivative plot shown.
- Issues introduce significant error to results for permeability and skin.
- Corrections for issues are demonstrated which reduce errors to acceptable levels.